Flooding is expected to subside in the Bahamas later on Thursday, although it could persist in Cuba, Jamaica, Haiti and the Dominican Republic, the US National Hurricane Center said.

The storm, one of the most powerful ever recorded, was made four times more likely because of human-caused climate change, according to a study by Imperial College London.

It was forecast to pass over Bermuda by late Thursday packing maximum sustained winds near 105 miles (165 kilometers) per hour, with the government urging residents to take precautionary measures against the still-powerful storm.

Melissa smashed into both Jamaica and Cuba with enormous force, and residents were assessing their losses and the long road to recovery.

Communications and transportation access remains largely down in both nations, and comprehensive assessment of the damage could take days.

In the east of the communist island of Cuba, which is battling its worst economic crisis in decades, people struggled through inundated streets lined with flooded and collapsed homes.

The storm smashed windows, downed power cables and mobile communications, and tore off roofs and tree branches.

Melissa "killed us, because it left us destroyed," said Felicia Correa, who lives in the La Trampa community near El Cobre.

"We were already going through tremendous hardship. Now, of course, we are much worse off," she told AFP.

Some people cleared debris or tried to repair damaged roofs, as others ventured out in search of food as shops began reopening.

Cuban authorities said about 735,000 people had been evacuated -- mainly in the provinces of Santiago de Cuba, Holguin and Guantanamo.

- 'Disaster area' -

The United States said it was in contact with the governments of Jamaica, Haiti, the Dominican Republic and the Bahamas, and US Secretary of State Marco Rubio said rescue and response teams were en route.

He later included ideological foe Cuba, saying the US is "prepared to offer immediate humanitarian aid to the people of Cuba affected by the Hurricane."

The UK government announced pound2.5 million (about $3.3 million) in emergency funding for the region, and also said it was chartering "limited" flights to help British nationals leave.

In Jamaica, UN resident coordinator Dennis Zulu told reporters Melissa had brought "tremendous, unprecedented devastation of infrastructure, of property, roads, network connectivity."

Authorities there have said confirming reports of deaths was difficult as access to the hardest-hit areas was limited, and some people were still unable to reach family and loved ones.

"What I will say is there have been casualties and we do anticipate based on our information that there'll be more," government minister Desmond McKenzie said during a briefing.

- 'Everything is gone' -

Gregoire Goodstein, the interim UN Humanitarian Coordinator for Haiti, said the death toll in that island nation had risen to 24 people.

Civil defense agency head Emmanuel Pierre had earlier said at least 10 children were killed in flooding as the hurricane shaved past earlier this week.

Hurricane Melissa tied the 1935 record for the most intense storm ever to make landfall when it battered Jamaica on Tuesday, according to the US National Oceanic and Atmospheric Administration (NOAA).

In Seaford Town, farmer and businessman Christopher Hacker saw his restaurant and nearby banana plantations flattened.

"Everything is gone," he told AFP.

Such mega-storms "are a brutal reminder of the urgent need to step up climate action on all fronts," said UN Climate Change Executive Secretary Simon Stiell.